#include<vector>
#include<iostream>
using namespace std;
int pivotIndex(vector<int>& nums)
{
    int n = nums.size();
    vector<int> f(n);
    vector<int> g(n);
    for (int i = 1; i < n; i++)
    {
        f[i] = f[i - 1] + nums[i - 1];
    }
    for (int i = n - 2; i >= 0; i--)
    {
        g[i] = g[i + 1] + nums[i + 1];
    }
    for (int i = 0; i < n; i++)
    {
        if (f[i] == g[i])
            return i;
    }
    return -1;
}

int main()
{
    vector<int> v1 = { 1,2,3 };
    cout << pivotIndex(v1);
    return 0;
    
}